Safety latch



Nov. 1., 1960 H. MORRIS, JR

SAFETY LATCH Filed Jan. 11. 1956 M703. Han'gMmmJ:

ms'mmwx SAFETY LATCH Harry Morris, Jr., Youngwood, Pa., assignor to Robertshaw-Fulton Controls Company, Richmond, Va., a corporation of Delaware Filed Jan. 11, 1956, Ser. No. 558,570

Claims. (Cl. 74-548) This invention relates to latching means and more particularly to a safety latch.

The invention has particular utility when incorporated in a combination valve and timing mechanism wherein the timing mechanism is utilized to control the opening of a valve, although as will become apparent to those skilled in the art, the utility of the invention is not limited to this application.

There has been a general trend toward domestic cook ing ranges which provide time control of the top burners as well as the oven burner. This control may be achieved by utilizing an escapement type clock mechanism to open and close a valve member in accordance with a time program adjustable by the operator.

One form of current devices of the described type utilizes a gas cock and a timer valve for independently controlling fuel flow through a passageway. A dial carried by the gas cock for adjusting the same contains a timer unit which is operatively connected to the timer valve. For setting the timer unit and its associated valve, a second dial is carried by the first said dial and connected to the timer unit by means of an axially movable and rotatable stem.

To set the timing unit in such devices, it is necessary for the operator to push the timer dial and stem inwardly and then rotate the same relative to the dial for the shut-0d cock. With such an arrangement, it has been possible for the operator to set the timer unit in any position of the shut-off cock, resulting in misadjustment on the part of the operator and errors in cooking time.

It is an object of this invention to permit the setting operation only in the Off position of the shut-ofi cock.

Another object of this invention is to construct an approved safety latch adaptable for various applications.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings wherein:

Fig. 1 is an exploded perspective view of a portion of a combination control of the described type showing the invention incorporated therewith.

Figs. 2 and 3 are front views of the control shown in Fig. 1 with the dial 18 removed and showing different controlling positions of the parts.

Referring to the drawings, a combination gas cock and timer valve in which the invention is incorporated is partially shown in Fig. l as including a casing carrying a manually operable dial 12 which is connected to a shut-off cock (not shown) positioned within the casing 10. Rotation of the dial 12 serves to rotate the cock between open and closed positions in a manner well known in the art.

As is customary in such devices, an escapement clock mechanism (not shown) is positioned within the dial 12 and operatively connected to a valve member (not shown) positioned within the casing 10. Adjustment means are provided for setting the clock mechanism to various time settings at which the same will actuate its associated valve member between positions. This adjustment means in- Patented Nov. 1,1960

ice

cludes a rotatable and axial movable stem 14 connected to the clock mechanism at one end (not shown) and having its other end extending from the upper side of the dial 12 in axial alignment therewith into a recess 16 formed in the exterior end of the dial 12. A second smaller diameter dial 18 is adapted to be received by the stem 14 to enclose the recess 16.

Preferably, the dial 12 is provided with suitable indicia 20 which are cooperable with an index 22 on the casing 10 to indicate various positions of the shut-01f cock. The dial 18 is also provided with suitable indicia 24 which are cooperable with the OE index 20 to indicate various time settings of the dial 18. v V

The structure thus far described is mounted on the front panel of a gas cooking range in the position shown with the axis defined by the dials 12 and 18 in a horizontal position. To set the timing mechanism the operator must push inwardly on the dial 18 and then rotate the same clockwise relative to the dial 12 to a desired setting. To turn the shut-off cock to the On position, the operator must rotate the dial 12 counterclockwise, such rotation moving the assembly comprising the dial 12, dial 18, and stem 14 counterclockwise as a unit.

For controlling the time setting operation of the dial 18, a hook-shaped lever 26 is pivoted at one end thereof on a pin 28 carried by the dial 12 within the recess 16- and has the other end thereof partially encircling the stem 14. The position of the lever 26 is influenced by the force of gravity, and in the Off position of the dial 12 as shown in Figs. 1 and 2, the lever 26 hangs clear of the stem 14 as shown in the drawing. However, upon counterclockwise rotation of the dial 12, the resulting movement of the pin 28 will shift the center of gravity of the lever 26 causing the same to swing to the left into engagement with the stem 14 as shown in Fig. 3.

The stem 14 is provided with a recess 30 on the periphery thereof which is positioned to receive the lever 26 when the same swings or gravitates to the left upon rotation of the dial 12. The positioning of the lever 26 whereby the same hangs free of the stem in the Off position (Figs. 1 and 2) of the dial 12 permits the setting of the timer dial 18 in the Off position of the dial 18 and shut-0E cock, however, upon counterclockwise rotation of the dial 12 to the On position (Fig. 3), the lever 26 swings or gravitates into the recess 30 thereby preventing axial movement of the stem 14 and the time setting operation.

It should now be apparent that the device is not limited to the above application but is adaptable to a variety of uses. Particularly, the device could be adapted for use in a device having thermoelectric safety shut-off means wherein it is desired to prevent resetting of the safety shut-off means except in various positions of a control dial or the like.

While only one embodiment of the invention has been herein shown and described, it will be apparent to those skilled in the art that the construction and arrangement of parts may be in other ways variously embodied or changed without departing from the scope of the invention as defined in the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In an interlocking mechanism, the combination comprising a rotatable member, a member movable reciprocally along an axis substantially coaxial to the axis of rotation of said rotatable member, an element loosely mounted on said rotatable member and operative to gravitate relative thereto upon rotation of said rotatable member, and interlock means formed on said reciprocal member engageable by said element during said gravitation thereof for locking said reciprocal member against reciprocal movement.

2. A safety latch comprising a rotatable member, a

member extending through said rotatable member in axial alignment therewith and movable axially relative thereto, a hooked shaped lever pivoted at one end thereof on said rotatable member, the pivot point of said lever being spaced from the center of rotation of'said rotatable.

member to effect pivotal movement of said lever, relative to said rotatable member by gravity upon rotation: of said rotatable member to a predetermined position, and-"interlock means on said axially movable member for engagement by said lever upon movement thereof to lock-said axially movable member against axial movement;

3-. In an interlocking mechanism, the combination comprising a rotatable member, a member movable reciprocally along an axis substantially coaxialto the axis of rotation of said rotatable member, said reciprocal member having a recess therein, a locking member supported on said rotatable member and operative upon rotation of said rotatable member to a predetermined angular position to engage said recess to lock said reciprocal member against reciprocal movement.

4. In an interlocking mechanism, the combination comprising a rotatable member, a member movable reciprocally along an axis substantially coaxial to the axis of rotation of said rotatable member, interlock means on said movable member, and a locking member supported on said rotatable member and operative upon rotation of said rotatable member to engage said interlock means to lock said movable member against movement relative to said rotatable member.

5. In an interlocking mechanism, the combination comprising a rotatable member, a member movable reciprocally along an axis substantially coaxial to the axis of rotation of said rotatable member, said reciprocal member having a recess therein, a lever pivoted at one end on said rotatable member and having the other end thereof movable under the influence of gravity upon rotation of said rotatable member to a predetermined angular position to engage said recess to lock said reciprocal member against reciprocal movement.

References Cited in the file of this patent UNITED STATES PATENTS 487,077 Rapson Nov. 29, 1892 759,013 Rawlings May 3, 1904 1,063,260 Herman June 3, 1913 1,076,206 Gerhart Oct. 21, 1913 1,588,289 Yenichek June 8,1926 1,596,451 Rawlings Aug. 17, 1926 2,187,118 Ficklin, Jan. 16, 1940 2,196,779 Perrson Apr. 9, 1940 2,684,142 Willyard et al. July 20, 1954 2,727,406 Opocensky Dec. 20, 1955 2,810,050 Johnson Oct. 15,, 1957 2,824,461 Hoeltje et al. Feb. 25, 1958 FOREIGN PATENTS 3,269 Great Britain Mar. 1, 1915 568,849 France Q Dec. 26, 1923 

